Caffeine (C8H10N4O2) is an alkaloid naturally occurring in coffee and coca beans cola nuts and tea leaves. Caffeine is described as a methylated xanthine alkaloid derivative (1,3–7 Trimethyl xanthine). Caffeine is water soluble above 175° F. and is soluble in methanol, ethanol etc. In mammals ingested caffeine is rapidly absorbed, metabolized and excreted in the urine as methyl Xanthine derivatives. Caffeine is mildly stimulating and is used as a therapeutic agent.
Caffeine has become a ubiquitous drug. Caffeine is widely distributed in pharmaceutical preparations and beverages. It has a variety of biological effects. It stimulates the central nervous system, shows toxicity when fed excessively and is even mutagenic in-vitro. Theobromine shows caffeine like pharmacological activities but does not cause excessive reaction as caffeine, so used as diuretic.
Many of the physiological effects of coffee beverage are due to their caffeine content. Dr. Karal Wimmer of Germany invented the process of removing caffeine from coffee. This process is known as decaffeination and the product is known as “Caffeine free Coffee” Reference may be made to the work on Coffee Solubilization: Commercial Processes and Techniques, Pintauro and Nicholas, D., (1975), wherein they have used methylene chloride for decaffeination of coffee. The drawback of this process is that the flavor elements and oil are drawn off from the beans; presence of residual solvent, which is not safe for human health and the time taken for the whole process, is more than 24 hours.
Reference may be made to the work of Zeller and Saleeb, Proceedings of 18th ASIC Colloquium (Helsinki), 168–172, (1999), wherein they have reported decaffeination of coffee beans using Ethyl Acetate. The drawback of this method is, it involves the use of organic solvent, which makes the process hazardous to health, expensive, time consuming and highly labour intensive.
Reference may be made to Hinman and Saleeb (1984), (General Foods Corp.), European Patent No.: EP-0140269, Coffee Technology; wherein they have reported the decaffeination of coffee by Charcoal or carbon. The drawbacks of this process are loss of flavor elements and colour, presence of residual caffeine in the product in addition to the longer time duration involved in the whole process.
Reference may be made to a patent by General Foods Corporation, USA, (1973), U.S. Pat. No.: Br. 1,313,047, Coffee Technology, wherein they have reported the use of Triglycerides. The drawbacks of this process are the loss of flavor and incomplete removal of caffeine from the final product.
Reference may be made to the work of Katz, S. N, Coffee Technology, (1987), wherein he has reported the use of supercritical CO2 for decaffeination. The drawback of this process is that although it does not affect the quality of the final product, it necessitates the extraction of caffeine to the surface of the bean by steam and involves very high costs and the caffeine is not completely removed from the final product.
Reference may be made to the work of Michael Gluck and Franz Lingens (1987), Applied Microbiology and Biotechnology, 334–340, on the studies on microbial production of theobromine and heteroxanthine from caffeine wherein they have used a strain of Pseudomonas putida. The drawbacks of this process are that the cells grow very slow in the medium containing caffeine, degradation of caffeine was very slow and the accumulation of products was too low for commercial purposes and the products produced in this process have effects similar to that of caffeine.
Reference may be made to the work of Wouter J. Middlehoven and Cor. M Bakker (1982) Eur. J Appl. Microbio. Biotechnol. 214–217, wherein they have reported the degradation of caffeine by immobilized cells of Pseudomonas putida strain C 3024 wherein they have immobilized the cells in beads of agar. The disadvantages of the process are the immobilization method tends to remove substances other than caffeine thus adversely affecting the flavor of roasted coffee and the growth yields of the cells are very low.
Reference may be made to a Swiss patent by Robert, F. D., Nestle Group (1981) Patent No. CH626781 “Decaffeination process” on decaffeination of vegetable material when exposed to the microorganism of the species Acinetobacter. The disadvantage of this method is that caffeine removal from the coffee extract is very slow and only about half of the initial caffeine content is removed from the extract.
Reference may be made to U.S. Pat. No. 4,228,191 (1980) wherein they have reported the use cell free extracts of Pseudomonad like organisms for decaffeination of aqueous caffeine containing liquids such as coffee extract. The disadvantage is the requirement of addition of cofactors for decaffeination, which are highly unstable.